This invention generally relates to guiding members for the advancement of catheters within a patient's vascular system in procedures such as percutaneous transluminal coronary angioplasty (PTCA) and particularly to such guiding members which facilitate the monitoring of pressure at the distal end thereof or the delivery of inflation fluid to a dilatation balloon.
In typical PTCA procedures a guiding catheter having a preformed distal tip is percutaneously introduced into the cardiovascular system of a patient and advanced therein until the distal tip thereof is in one of the patient's coronary arteries. A guidewire is introduced through the guiding catheter and advanced out of the distal end of the guiding catheter and into the patient's coronary vasculature until the distal end of the guidewire crosses a lesion to be dilated. A dilatation catheter having an inflatable balloon on the distal portion thereof is then advanced into the patient's coronary anatomy over the previously introduced guidewire, with the guidewire slidably disposed within an inner lumen of the dilatation catheter, until the dilatation balloon is properly positioned across the lesion. Once in position across the lesion, the balloon is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g., greater than 4 atmospheres) to compress the atherosclerotic plaque of the lesion against the inside of the artery wall. The balloon is then deflated so that the dilatation catheter can be removed and blood flow resumed through the dilated artery.
Steerable dilatation catheters with built-in guiding members are being used with increasing frequency because the deflated profiles of such catheters are generally much smaller than conventional dilatation catheters and a smaller profile allows the catheter to cross tighter lesions and to be advanced much deeper into the patient's coronary anatomy. Additionally, the use of steerable low-profile dilatation catheters can shorten the time for the angioplasty procedures because there is no need to first advance a guidewire through the stenosis and then advance a conventional dilatation catheter over the previously placed guidewire.
Further details of dilatation catheters, guidewires, and the like for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,468,224 (Enzmann et al.); U.S. Pat. No. 4,516,972 (Samson), U.S. Pat. No. 4,538,622 (Samson et al.); U.S. Pat. No. 4,582,181 (Samson); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,619,263 (Frisbie et al.) U.S. Pat. No. 4,638,805 (Powell); U.S. Pat. No. 4,641,654 (Samson et al.); U.S. Pat. No. 4,721,117 (Mar et al.); and U.S. Pat. No. 4,821,722 (Miller et al.) which are hereby incorporated herein in their entirety by reference thereto.
Efforts have been made, such as described in U.S. Pat. No. 4,582,181, to develop hollow guidewire systems which allow for the measurement of the fluid pressure at the distal end of the catheter from the proximal end of the catheter. However, usually such pressure sensing guidewires do not have the flexibility in the distal portion thereof to be advanced very far into a patient's vasculature, particularly the coronary arteries. What has been needed and heretofore unavailable is a guiding member which has sufficient flexibility in the distal portion thereof to be easily advanced through a patient's arteries and which can monitor from the proximal end thereof the fluid pressure within the patient's artery at the distal end of the guidewire. The present invention satisfies that need.